﻿using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Text;
using Volo.Abp.DependencyInjection;

namespace Paas.Pioneer.Domain.Shared.Helpers
{
	public class VerifyCodeHelper : ISingletonDependency
	{
		private string GenerateRandom(int length)
		{
			var chars = new StringBuilder();
			//验证码的字符集，去掉了一些容易混淆的字符
			char[] character = { '2', '3', '4', '5', '6', '8', '9', 'a', 'b', 'd', 'e', 'f', 'h', 'k', 'm', 'n', 'r', 'x', 'y', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };
			Random rnd = new Random();
			//生成验证码字符串
			for (int i = 0; i < length; i++)
			{
				chars.Append(character[rnd.Next(character.Length)]);
			}
			return chars.ToString();
		}

		private byte[] Draw(out string code, int length = 4)
		{
			int codeW = 110;
			int codeH = 36;
			int fontSize = 22;

			//颜色列表，用于验证码、噪线、噪点
			Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue };
			//字体列表，用于验证码
			string[] fonts = new[] { "Times New Roman", "Verdana", "Arial", "Gungsuh", "Impact" };

			code = GenerateRandom(length);

			//创建画布
			using (Bitmap bmp = new Bitmap(codeW, codeH))
			using (Graphics g = Graphics.FromImage(bmp))
			using (MemoryStream ms = new MemoryStream())
			{
				g.Clear(Color.White);
				Random rnd = new Random();
				//画噪线
				for (int i = 0; i < 1; i++)
				{
					int x1 = rnd.Next(codeW);
					int y1 = rnd.Next(codeH);
					int x2 = rnd.Next(codeW);
					int y2 = rnd.Next(codeH);
					Color clr = color[rnd.Next(color.Length)];
					g.DrawLine(new Pen(clr), x1, y1, x2, y2);
				}

				//画验证码字符串
				{
					string fnt;
					Font ft;
					Color clr;
					for (int i = 0; i < code.Length; i++)
					{
						fnt = fonts[rnd.Next(fonts.Length)];
						ft = new Font(fnt, fontSize);
						clr = color[rnd.Next(color.Length)];
						g.DrawString(code[i].ToString(), ft, new SolidBrush(clr), (float)i * 24 + 2, (float)0);
					}
				}

				//将验证码图片写入内存流，并将其以 "image/Png" 格式输出
				bmp.Save(ms, ImageFormat.Png);
				return ms.ToArray();
			}
		}

		public string GetBase64String(out string code, int length = 4)
		{
			return Convert.ToBase64String(Draw(out code, length));
		}
	}
}